From what I read, the Open VM Tools source includes drivers for the most common emulated hardware, including vmxnet3, which would provide 10Gbit virtual NICs for VM hosts that have real ones. These are all apparently GPLv2 or LGPLv2 licensed, avoiding questions about ensuring ZS stays open source. VMware doesn’t even want anyone calling it “VMware Tools” if compiled from this source, as “VMware Tools” apparently still has some proprietary components where Open VM Tools does not.
Unfortunately I’m a Windows admin and have my hands full working. I attempted Linux From Scratch once, but that’s it. I’m not qualified to attempt this.